Cancer Drug Doesn't Speed Up Tumor Growth, Researchers Say

THURSDAY, Feb. 7 -- The anticancer drug Sutent (sunitinib) does not cause tumors to grow faster after treatment ends, according to a new study.

Previous research in animals suggested that tumor growth may accelerate after patients stopped taking Sutent. The new findings, from a study of kidney cancer patients, indicate that the drug does not pose lingering risks for humans.

The researchers analyzed data from a phase 3 clinical trial that led to Sutent's approval. They concluded that regardless of how long patients took the drug, it did not cause harm, did not speed up tumor growth and survival was not shortened after treatment ended, according to the findings published online Feb. 7 in the journal Cell Reports.

During treatment, Sutent slowed tumor growth and extended patients' lives, the investigators pointed out in a journal news release.

Sutent, which is approved for the treatment of several different cancers, targets proteins on the blood vessels that feed tumors.

"Last year, I was approached by two patients who had grave concerns about taking sunitinib due to an article [about research] conducted in animals. I realized that if clinical data exist that refute basic science, they must be published," study senior author Dr. Tito Fojo, of the U.S. National Cancer Institute, said in the news release.

These new findings should reassure patients, the study authors suggested.

"We hope [these findings] can be generalized to similar drugs but recognize that further studies will be needed," study first author Dr. Krastan Blagoev, of the U.S. National Science Foundation, said in the news release. "Nevertheless, other drugs also approved worldwide for a variety of cancers -- including sorafenib, pazopanib, and axitinib -- are similar to sunitinib, and this will give some reassurances that one need not expect things to get worse after such drugs are discontinued."